[tip:perf/core] perf: Add cycles to branch_info

[tip-bot for Andi Kleen]

Commit-ID:  71ef3c6b9d4665ee7afbbe4c208a98917dcfc32f
Gitweb:     http://git.kernel.org/tip/71ef3c6b9d4665ee7afbbe4c208a98917dcfc32f
Author:     Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Sun, 10 May 2015 12:22:42 -0700
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Aug 2015 10:16:57 +0200

perf: Add cycles to branch_info

Intel Skylake supports reporting the time in cycles a branch in the LBR
took, to give a rough indication of the basic block performance.

Export the cycle information in the branch_info structure.
This can be done by just reusing some currently zero padding.

This is just the generic header change. The architecture
still needs to fill it in.

There's no attempt to convert to real time, as we really
want cycles here.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: eranian@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1431285767-27027-5-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/uapi/linux/perf_event.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 022d0ac..2881145 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -951,6 +951,7 @@ union perf_mem_data_src {
  *
  *     in_tx: running in a hardware transaction
  *     abort: aborting a hardware transaction
+ *    cycles: cycles from last branch (or 0 if not supported)
  */
 struct perf_branch_entry {
 	__u64	from;
@@ -959,7 +960,8 @@ struct perf_branch_entry {
 		predicted:1,/* target predicted */
 		in_tx:1,    /* in transaction */
 		abort:1,    /* transaction abort */
-		reserved:60;
+		cycles:16,  /* cycle count to last branch */
+		reserved:44;
 };
 
 #endif /* _UAPI_LINUX_PERF_EVENT_H */
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